var initPhotoSwipeFromDOM = function(gallerySelector) {
  var parseThumbnailElements = function(el) {
    var thumbElements = el.childNodes,
      numNodes = thumbElements.length,
      items = [],
      figureEl,
      linkEl,
      size,
      item;
    for (var i = 0; i < numNodes; i++) {
      figureEl = thumbElements[i]; // <figure> element
      if (figureEl.nodeType !== 1) {
        continue;
      }
      linkEl = figureEl.children[0]; // <img> element
      console.log(linkEl);
      item = {
        src: linkEl.getAttribute('src'),
        w: linkEl.naturalWidth,
        h: linkEl.naturalHeight
      };
      // 预加载缩略图
      item.msrc = linkEl.getAttribute('src');
      item.el = figureEl; // save link to element for getThumbBoundsFn
      items.push(item);
    }
    return items;
  };
  var closest = function closest(el, fn) {
    return el && (fn(el) ? el : closest(el.parentNode, fn));
  };
  var onThumbnailsClick = function(e) {
    console.log('onThumbnailsClick');
    e = e || window.event;
    e.preventDefault ? e.preventDefault() : e.returnValue = false;
    var eTarget = e.target || e.srcElement;
    var clickedListItem = closest(eTarget, function(el) {
      return (el.tagName && el.tagName.toUpperCase() === 'FIGURE');
    });
    if (!clickedListItem) {
      return;
    }
    var clickedGallery = clickedListItem.parentNode,
      childNodes = clickedListItem.parentNode.childNodes,
      numChildNodes = childNodes.length,
      nodeIndex = 0,
      index;
    for (var i = 0; i < numChildNodes; i++) {
      if (childNodes[i].nodeType !== 1) {
        continue;
      }
      if (childNodes[i] === clickedListItem) {
        index = nodeIndex;
        break;
      }
      nodeIndex++;
    }
    if (index >= 0) {
      openPhotoSwipe(index, clickedGallery);
    }
    return false;
  };
  var photoswipeParseHash = function() {
    var hash = window.location.hash.substring(1),
      params = {};
    if (hash.length < 5) {
      return params;
    }
    var vars = hash.split('&');
    for (var i = 0; i < vars.length; i++) {
      if (!vars[i]) {
        continue;
      }
      var pair = vars[i].split('=');
      if (pair.length < 2) {
        continue;
      }
      params[pair[0]] = pair[1];
    }
    if (params.gid) {
      params.gid = parseInt(params.gid, 10);
    }
    return params;
  };
  var openPhotoSwipe = function(index, galleryElement, disableAnimation, fromURL) {
    var pswpElement = document.querySelectorAll('.pswp')[0],
      gallery,
      options,
      items;

    items = parseThumbnailElements(galleryElement);
    options = {
      tapToClose:true, // 点击关闭
      galleryUID: galleryElement.getAttribute('data-pswp-uid'),
      getThumbBoundsFn: function(index) {
        // See Options -> getThumbBoundsFn section of documentation for more info
        var thumbnail = items[index].el.getElementsByTagName('img')[0], // find thumbnail
          pageYScroll = window.pageYOffset || document.documentElement.scrollTop,
          rect = thumbnail.getBoundingClientRect();
          console.log(rect);
        return {
          x: rect.left,
          y: rect.top + pageYScroll,
          w: rect.width
        };
      },
    };
    if (fromURL) {
      if (options.galleryPIDs) {
        for (var j = 0; j < items.length; j++) {
          if (items[j].pid == index) {
            options.index = j;
            break;
          }
        }
      } else {
        options.index = parseInt(index, 10) - 1;
      }
    } else {
      options.index = parseInt(index, 10);
    }
    if (isNaN(options.index)) {
      return;
    }
    if (disableAnimation) {
      options.showAnimationDuration = 0;
    }
    options.showHideOpacity  = true
    gallery = new PhotoSwipe(pswpElement, PhotoSwipeUI_Default, items, options);
    gallery.init();
  };
  var galleryElements = document.querySelectorAll(gallerySelector);
  for (var i = 0, l = galleryElements.length; i < l; i++) {
    galleryElements[i].setAttribute('data-pswp-uid', i + 1);
    galleryElements[i].onclick = onThumbnailsClick;
  }
  var hashData = photoswipeParseHash();
  if (hashData.pid && hashData.gid) {
    openPhotoSwipe(hashData.pid, galleryElements[hashData.gid - 1], true, true);
  }
};
initPhotoSwipeFromDOM('.my-gallery');